VulnerabilityPublished 18 Oct 2026

CVE-2026-98525: Linux kernel · mctp: route: iterate socket tag list in mctp_lookup_prealloc_tag()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f178300e2f56ca9ec2a3a0090608730bbee0af7b : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f178300e2f56ca9ec2a3a0090608730bbee0af7b, e35cb500dd14882f8dee61783fccd1823fd3ab0d, 09299addab11857e92eca55cd8ef3350b927c90c +1

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to f178300e2f56ca9ec2a3a0090608730bbee0af7b, e35cb500dd14882f8dee61783fccd1823fd3ab0d, 09299addab11857e92eca55cd8ef3350b927c90c or 26cc0e69cce062cd3aa6fae33074684669c35a71.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 63ed1aab3d40aa61aaa66819bdce9377ac7f40fa, < f178300e2f56ca9ec2a3a0090608730bbee0af7b	Fixed in f178300e2f56ca9ec2a3a0090608730bbee0af7b
LinuxLinux	Affected ≥ 63ed1aab3d40aa61aaa66819bdce9377ac7f40fa, < e35cb500dd14882f8dee61783fccd1823fd3ab0d	Fixed in e35cb500dd14882f8dee61783fccd1823fd3ab0d
LinuxLinux	Affected ≥ 63ed1aab3d40aa61aaa66819bdce9377ac7f40fa, < 09299addab11857e92eca55cd8ef3350b927c90c	Fixed in 09299addab11857e92eca55cd8ef3350b927c90c
LinuxLinux	Affected ≥ 63ed1aab3d40aa61aaa66819bdce9377ac7f40fa, < 26cc0e69cce062cd3aa6fae33074684669c35a71	Fixed in 26cc0e69cce062cd3aa6fae33074684669c35a71
LinuxLinux	Affected =5.18	Fixed in–

AI-suggested

A fix is available and has been applied in specific Linux kernel commits (identified by hashes f178300e2f56ca9ec2a3a0090608730bbee0af7b, e35cb500dd14882f8dee61783fccd1823fd3ab0d, 09299addab11857e92eca55cd8ef3350b927c90c, 26cc0e69cce062cd3aa6fae33074684669c35a71). Users should update to a kernel version including these fixes to remediate the vulnerability.

Description

A vulnerability in the Linux kernel's MCTP socket handling allows sockets within the same network namespace to misuse preallocated tags belonging to other sockets. The flaw occurs because the function mctp_lookup_prealloc_tag() iterates over a namespace-wide tag list instead of the socket's own tag list, enabling tag consumption across sockets improperly. This issue has been fixed by restricting tag matching to the socket's own tag list.

Impact

The vulnerability allows unauthorized MCTP sockets within the same network namespace to use and consume preallocated tags belonging to other sockets. This could lead to improper tag usage and potential interference between sockets, possibly affecting communication integrity or resource management within the MCTP protocol implementation in the kernel.

Summary

CVE-2026-98525 is a Linux kernel vulnerability in the MCTP route code where mctp_lookup_prealloc_tag() incorrectly iterates over the per-network namespace keys list instead of the socket's own tag list. This allows any MCTP socket in the same network namespace to use and consume another socket's preallocated tag, violating tag ownership boundaries. The fix changes the iteration to the socket's own tag list, ensuring only tags allocated by that socket are matched. The vulnerability was tested on Linux 7.3.0-rc3, demonstrating that without the fix, a socket can send packets using another socket's preallocated tag, while with the fix, such attempts fail.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:53 UTC

Technical details

References

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